And if it get's in your history, it'll crash every time the character shows up again. I ended up having to delete the entry manually:
$ sqlite3 ~/Library/Safari/History.db
SQLite version 3.19.3 2017-06-27 16:40:08
Enter ".help" for usage hints.
sqlite> delete from history_items where url = "https://pastebin.com/9Tr8ytTr";
Ohhh nice. Yep, definitely crashed Safari on OSX 10.13.3 when the character is in the address bar. Firefox seems fine and is my daily driver, fortunately
Firefox Developer Edition 59.0b9 here on latest High Sierra. Opening the link doesn't crash anything, but highlighting the paste did. I would have expected the tab at most to crash, but it took out the whole browser
Original iPad here running iOS 9.3.5. Everything works as expected. I can't seem to crash anything with this string. Oh well, I guess that's the benefit of not upgrading, ever.